Long story short: regular merciful courts and about 40 estate points in authority let him/me crank up the tax rate over 20% and keep 6+1 knights with respectable weekly incomes without losing any control or production in the region.
In short: Inherit very poor barony, add lots of estates, rival marches in both income and vassals, flaunt what ya got
You must have a very, very different concept of what "respectable weekly income" is!
A rough estimate says that running 20% (at 150 gold) gets you ~215 and, 25% gets you ~268.
The 268 evenly divided by 7 works out to average income of 38 gold a week. While impressive
from a poor region, that's far from respectable income and you also had to run court to maintain
that? With such income it would take years to build and enlarge a single recruitment center...
(a reasonable infantry center took me 100+300 and needs another 500 to go to size 3)